Regulator



NOV. 12, 1940. J, F. KQVALSKY 2,221,586

REGULATOR Filed May 5, 1939 UNITED STATES- PATENT OFFICE REGULATOR Joseph F4 Kovalsky, Turtle Creek, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 5, 1939, Serial No. 271,908

8 Claims. (Cl. 171-2`29) My invention relates to regulators of the type ing an anti-hunting influence into the primary wherein aprimary control relay is continuously control element of the regulator without t-he vibrated for intermittently short circuiting a regnecessity of using the heavier and more costly ulating resistor, such as are employed for govfeed-back transformer, or equivalent device.

erning the excitation of alternating current gen- It is a further object of the invention to pro- 5 erators to maintain a regulated quantity, such as vide a circuit of the character described which the generator voltage, at a desired value. In such isolates the iield regulating circuit and the reguregulators, a vibrating relay is caused to operate lator control circuit of the equipment from each to intermittently short circuit a regulating resisother to prevent the flow of direct current there- 10 tor or a portion thereof to vary the resistance between. w in circuit with the generator iield winding for Other objects and advantages of my invention maintaining the regulated quantity at the dewill be apparent from the following description sired value. The elective value of the resistor is of one preferred embodiment thereof, reference determined by the ratio between the durations being had to the accompanying drawing, in

l5 of time in which the resistor is short circuited which: 15

' and the duratiOnS of time during which the short Figure 1 is a diagrammatic view of apparatus circuit is removed. and circuits illustrating a preferred embodiment `It is desired to provide such regulators with of the invention;` l means for anticipating the corrective action Fig. 2 is a view of curves illustrating varying caused by a change in the eld excitation of the current values; 20

generator prior to a completion of this action Fig. 3 is a curve showing the relationship beat the terminals 0f the generator in order to pretween varying values of certain quantities; and vent overtravel in the corrective influence. Such Fig. 4 is a View, partly in section and partly in stabilizing or anti-hunting forces have in the past side elevation, of a regulator relay that may be been determined, in small regulators, by variaemployed for controlling the output voltage of 25 tions in the voltage drop across the eld winding, the regulated generator. or in the field current as the voltage applied to Referring to Figure l of the drawing, an a1- the eld winding is varied for adjusting the externating current generator I is illustrated for citation of the machine. supplying energy to a three-phase circuit repre- One conventional manner of introducing such sented by conductors 2, 3 and 4 and having a 80 stabilizing or anti-hunting forces into the pri-y field winding 5 that is energized from an exciter mary relay circuit of dynamic type regulators is 6 having a field winding 'I that is supplied with the feed-back transformer, the primary winding direct current energy from a source represented of Which is connected to be energized in accordby conductors 8 and 9. A regulating resistor I2 ance with the field voltage or eld current and is provided in circuit with the field winding 1, the 35 the secondary winding of which is connected in opposite ends of which are connected to contact the regulating relay control circuit to introduce members I3 and I4, respectively, of a regulating voltage components into this circuit in a direcrelay I5 of the vibrating type for varying the tion and of a value determined by the direction effective value of the resistor I2 in a Well known and rate of change of the excitation of the conmanner. A moving lever` I6 is provided and is 40 trolled machine. The use of feed-back transmounted to be actuated about a pivot axis I'I for formers for this purpose introduces -errors due to eiiecting movement of the movable contact memtemperature changes in the copper conductors of ber I4 into and out of engagement with the fixed the transformers which is undesirable in many Contact member I3. The lever I 6 is biased in applications. In order to avoid such temperature one direction by a spring I8 and in the opposite 45 errors, it is necessary to design the transformer direction by an electromagnet including a core with relatively large diameter wire of a relativestructure 2l and series connected windings 22 ly few turns. In order to retain the same time and 23 that are connected in series to be enerconstant of the transformer with a fewer numgized in accordance with the output of a fullber of turns, it is necessary to increase the amount .f wave rectifier 24. The regulator control circuit 50 of iron in the magnetic circuit so that the transextends from one output terminal of the rectifier former becomes very large and heavy. 24 through conductor 25, windings 23 and 22,

It is an object of this invention to provide a conductor 26, voltage adjusting rheostat 21 and regulator for alternating current generators emconductor .28 to the other output terminal of the ploying a simple condenser circuit for introducrectifier 24. The inputto the rectifier 24 is con- 55 nected through a transformer 23 from alternating current circuit conductors 3 and 4 that is a measure of the terminal voltage of the generator I.

Means is provided for varying the current through the regulator relay windings 22 and 23 upon the engagement of the relay contact members I3 and I4 for introducing an anti-hunting influence into the operation of the relay, which consists of connecting the field regulating circuit and the regulator relay control circuit together through a condenser circuit which permits double frequency ripple current to flow from the rectifier 24 while preventing unidirectional current from iiowing. The condenser circuit, as illustrated, consists of two condenser portions 3| and 32, the condenser portion 3I being connected from a junction point 33 between the voltage adjusting rheostat 21 and the regulator relay winding to a Junction point 34 between the field winding 1 and the iield regulating resistor' I2. The condenser portion 32 is connected between a junction point 35, at the opposite end of the voltage adjusting resistor 21 from the Junction point 33, to a Junction point 33 at the opposite end of the regulating resistor I2 from the junction point 34.

Referring to Fig. 4, the regulator there illustrated may be employed as the primary relay of the regulator system organized in accordance with my invention and corresponds substantially to the regulator constituting the subject matter '0f United States Patent N0. 1,820,712 for VOltage regulator, issued August 5, 1931, to Walter Schaelchlin and assigned to the same assignee as this application. The regulator comprises a magnetic structure 2I including a central or winding leg 38 and an outer leg 39 terminating ing an annual portion 42 surrounding one end of the winding leg 33. 'I'he winding 22 is provided for magnetizing the core and is mounted upon the major portion of the winding leg 33 and conneoted in series circuit relation with .the smaller winding 23 that is mounted upon a movable bifurcated arm I6. The winding 23 is positioned with its conductors surrounding one end of the winding leg 33 of the magnet structure and within the flux path between the winding leg and the annular portion 23 that surrounds the left-end of the winding leg 33, as viewed in Fig. 4.

'I'he annular portion 42 of the magnet structure is provided with upwardly extending bracket portions 43, one of which is shown in dotted lines in Fig. 4, and upon which the bifurcated arm I3 is supported by means of a square bar 44 extending through the vanes of the arms I 6 between the two bracket portions 43, the edge I1 of which serves as the axis for the moving structure. A similar bar 4I extends between the vanes of .the arm I6 to provide a tulcrum point about which a force is applied to bias the arm I against the magnetic pull of the armature winding 23. 'Ihe bars 44 and 4l are held in their illustrated pomtions by means of clamping members 43 and 41 that are held together by a bolt 43.

The movable coil 23 is mounted upon a metal sleeve ll that is attached to the vanes of the arm I3 by any suitable means, such as rivets 52. 'I'he vanes of the arm I3 are connected at their upper ends by means of a transverse member 53 to which a bracket 54 is attached for carrying the movable contact member I4. 'I'he stationary contact member I3 that cooperates with the movable contact member I4 is mounted on the panelboard II by a suitable means, such as a bracket 53 and screw 51. The biasing spring I3 that is provided is attached at one end to an adjusting screw I8 carried by bracket 59 that extends upwardly from the magnet structure. The other end of the spring I3 is attached to a fiat hook member 62 which engages the bar 45 to actuate the arm I6 in a clockwise direction about the axis I1, as viewed in Fig. 4, thereby normally maintaining the contact members I3 and I4 in engagement.

The rectifier 24 may be the single-phase double-wave dry type, and will deliver to the output rcircuit a uni-directional current having a doubleirequency ripple, as shown by the curve 63 above the zero-line in Fig. 2. If the voltage applied to the rectiiier from the transformer 23 is a 60- cycle alternating current, the ripple shown in Fig. 2 will be a 1Z0-cycle ripple. With a constant voltage applied .to the rectifier 24 from the transformer 28, and with the contact members I3 and I4 separated, the current through the relay windings 22 and 23 will have the same constant effective value, as shown by the full line curve 63 in Fig. 2. When the contact members I3 and I4 are brought into engagement, the ripple current flowing through condenser portions 3| and 32 and the contact members I3 and I4 will cause the eiective value of the ripple current through the windings 23 and 22 to increase to some greater value as shown by the dotted line 64 in Fig. 2.

'I'he curve 31 in Fig. 3 shows the effect oi' varying the capacitance of ythe condensers 3| and 32 on the increase in current owing through the relay coil when the contact members I3 and I4 are in engagement.

The operation oi' the regulator is as follows: When the generator I is started and the voltage is below its normal or desired value, the contact member I4 is biased by the spring I8 into engagement with the contact member I3, thus short circuiting 4the regulating resistor I2 and causing the full voltage of the source 3-3 to be applied to the eld winding 1 of the exciter generator to increase the exciter generator voltage and the voltage of the main generator I. As the voltage of the generator builds up to its desired value, which is determined by adjusting the tension of the spring I8 and the value of the resistor 21, the movable winding 23 will be attracted toward the winding 22 against the bias of the spring I8, thus causing the contact members I4 and I3 to separate and introduce the resistor I2 in the field winding circuit of the exciter generator. The introduction of the resistor I2 in the field circuit causes the voltage of the exciter generator 3 and of the main generator I to decrease, thus again decreasing the energization of the windings 22 and 23 and permitting the reengagement of the contact members I4 and I3. 'I'he regulator will thus continue to vibrate causing repeated engagement and separation of the contact members I4 and I4 to correspondingly vary the effective value of the resistor I2 in the field winding circuit and eilect slight alternate increasing and decreasing energlzation of the field windings of the .two machines within narrow limits to maintain the constantly desired voltage on the generator I.

Engagement of contact members I3 and I4 causes the ripple current through the relay windings to increase from the value indicated by the -line 33 in Fig. 2 to the value indicated by the line 64, causing the pull on the armature winding 23 to increase sooner than it otherwise would. to cause a separation of the contact members I3 and Il earlier than would be the case if the separation occurred only upon a completion of the increase in voltage between conductors 3 and 4 to the desired value. The time lag between a particualr iield current (in the exciter and in the generator) and the ultimate increase in voltage caused thereby causes a slight yfurther increase in rthe voltage at the generator terminals, thus making -it desirable to separate the contact members I3 and I4 slightly before a completion in the rise of a voltage to the desired value.

It will be noted that with the condensers 3| and 32 connected as shown in Fig. 1, the control circuit for the relay windings 22 and 23 is isolated so far as direct current is concerned, since direct current will not fiow through a condenser. Thus, should, for any reason, a ground occur on any part of the iield winding circuit, this will not disturb :the operation of the regulator relay control circuit. In different applications of a vibrating regulator of the type disclosed to different sizes of machines, it is necessary to vary the ohms employed in the regulating resistor l2, which factor would modify the possible degree of anti-hunting to be obtained from a regulator of the type described,l as applied to different generator applications, if the anti-hunting were obtained by directly short circuiting the voltage adjusting resistor 21 through the regulator contacts I3 and I4. On the other hand, the increased current for introducing a stabilizing or anti-hunting influence into the regulator is, with applicants circuit arrangements, determined by the values of capacitance used in condenser portions 3| and 32, and remains the same for all machine applications independently ofthe differing conditions in the iield regulating circuit.

It will be apparent to any one skilled in the art that modifications in the circuits and apparatus illustrated may be made within the spirit of my invention, and I do not wish to be limited otherwise than by the scope of the appended claims.

I claim as my invention:

1. In a regulating system, an alternating current generator, means for controlling the excitation of` said generator comprising a eld energia. ing circuit including a field winding and a regulating resistor for adjusting the voltage applied to the iield winding, a regulating relay for intermittently short circuiting said regulating resistor having an operating winding, means for energia.. ing said winding in accordance-With a regulated characteristic of said generator comprising a rectifier supplied with alternating current at a voltage that is a measure of the regulated characteristic and a control circuit supplied with unidirectional current from the rectiiier and including the relay Winding, a condenser, and means operative upon the short circuiting of said regulating resistor for introducing said condenser in circuit with said relay winding for modifying the relay current to introduce an anti-hunting action into the operation of the relay.

2. In a regulating system, an alternating current generator, means for controlling the excitation of said generator comprising a field energizing circuit including a ield winding and a regulating resistor for adjusting the voltage applied to the field winding, a regulating relay for intermittently short circuitingsaid regulating resistor having an operating winding, means for energizing said Winding in accordance with a regulated characteristic of said generator comprising a rectifier supplied with alternating current at a voltage that is a measure of the regulated characteristic and a control circuit supplied with uni. directional current from the rectifier and includ- `ing the relay winding and a voltage adjusting gizing circuit includingl a iield winding and a' regulating resistor for adjusting the voltage applied to the iield winding, a regulating relay for intermittently short circuiting said regulating resistor having an operating winding, means for energizing said winding in accordance with a regulated characteristic of said generator comprising a rectiiier supplied with alternating current at a voltage that is a measure of the regulated characteristic and a control circuit supplied with uni-directional current from the recti. Iier and including the relay Winding and a voltage adjustingk resistor, a condenser, and means, operative upon the short circuiting of the regulating resistor for causing a current flow through the condenser in parallel circuit relation to the current iiowing through said voltage adjusting resistor to increase the iiow of current through the relay winding.

4. In a regulating system, an alternating current generator, means for controlling the excitation of said generator comprising a field energizing circuit including a eld winding and a regulating resistor for adjusting the voltage applied to the field winding, a regulating relay for intermittently short circuiting said regulating resistor having an operating Winding, means for energizing said Winding in accordance with a regulated characteristic of said generator comprising a rectifier supplied with alternating current at a voltage that is a measure of the regulated characteristic and a control circuit supplied with unidirectional current from the rectifier and including the relay winding and a voltage adjusting resistor, and condenser portions connected between the respective ends of said regulating resistor and the corresponding ends of said voltage adjusting resistor to isolate the circuits of the two resistors against the flow of unidirectional current therebetween.

5. In a regulating system, an alternating current generator, means for controlling the excitation of the generator comprising a iield winding circuit including a regulating resistor for adjusting the voltage applied to the field winding, a continuously vibrating regulating relay for intermittently short circuiting the regulating resistor to control is effective value, said relay having an operating winding, a control circuit including said operating winding and a voltage adjusting resistor, a source of unidirectional current for said control circuit comprising a rectifier energized from an alternating current circuit at a voltage that is a measure of the regulated quantity, condenser means connected between the field winding circuit and the control circuit to prevent the iiow of unidirectional current between these two circuits, said relay being effective, upon short circuiting said regulating resistor, to also cause a current flow through said condenser means in shunt relation to said voltage adjusting resistor and in series with said relay winding to increase the flow of current through the relay operating winding.

' 6. In a regulating system, an alternating current generator, means for controlling the excitation of the generator comprising a eld winding circuit including a regulating resistor for adjusting the voltage applied to the field winding, a continuously vibrating regulating relay for intermittently short circuiting'the regulating resistor to control its effective value, said relay having an operating winding, a control circuit including said operating winding and a voltage adjusting resistor, means for supplying unidirectional current to said control circuit comprising l5 a rectier energized from an alternating current circuit at a voltage that is a measure of the regulatedv quantity, condenser means connected between the ileld winding circuit and the control circuit to prevent the ow of unidirectional current between these two circuits, and means operative for short circuiting the regulating resistor and for applying a voltage across the condenser in series circuit with the relay winding to cause the iiow of ripple current from the rectier therethrough for causing a stabilizing component of current to ilow through the relay winding.

7. In a regulating system, an alternating current generator, means for controlling the excitation of said generator comprising a field energizing circuit including a field winding and a regulating resistor for adjusting the voltage applied to the field winding, a regulating relay for intermittently short circuiting said regulating resistor having an operating winding, means for energizing said winding in accordance with a regulated characteristic of said generator comprising a rectier supplied with alternating current at a voltage that is a measure of the regutherebetween, and common means for short circuiting the regulating resistor and for applying a voltage across the condenser in series circuit with the relay winding to cause the flow of ripple current from the rectifier therethrough for causing a stabilizing component of current to flow through the relay winding.

8. In a regulating system, an alternating current generator, means for controlling the excitation of the generator comprising a field winding circuit including a regulating resistor for adjusting the voltage applied to the eld winding,

' a continuously vibrating regulating relay for intermittently short circuiting the regulating resistor to control its effective value, said relay having an operating winding, a control circuit including said operating winding and a voltage adjusting resistor, means for supplying unidirectional current to said control circuit comprising a rectier energized from an alternating current circuit at a voltage that is a measure of the regulated quantity, condenser portions connected between the respective ends of said regulating resistor and said voltage adjusting resistor to isolate the circuits of these two resistors against the flow oi unidirectional current therebetween and to permit the flow of ripple current from the rectifier therethrough upon the short circuiting of the regulating resistor to eiect an antihunting action o! the regulator.

JOSEPH F. KOVALSKY. 

